That seems to make a lot of sense, I figured a diesel under heavy load would vibrate and such a lot more, probably just the firing of the engine shacking everything enough for me to feel it more. Seems to be around 900-1000 rpm when I notice it lol. I basically never floor any vehicle of mine. In my gasser's, 1/4-1/2 throttle was plenty to get the LOD reading on the scan gauge to around 80. My Corolla was great for it's shift points and not down shifting till 3/4-full throttle or the speed dropped too much.
I wouldn't mind getting a EGT gauge setup. Empty it's probably little to no concern unless the truck has a hotter tune in it, but with a load there's a lot more wind resistance and weight.
Not sure how much I mentioned about my dad's truck, but we are thinking the torque converter went out on it. My idea is to throw in the torque converter from the parts truck into it to test (still a lot of work), and if it made it go, decide on buying a new one or run the 300k miles one that's probably just fine and drive it. The more we research things, it sounds like either get the stick with these trucks, or spend the $3600+ to upgrade the stock auto trans to handle the power. I haven't found what all is replaced, I know the torque converter alone is something like $800 or so, input and output shafts are like $1200, standard rebuild kit for the clutches, seals, etc seem to run $100-600. Not sure what the big upgrade parts are, unless it's just the torque converter and shafts.
I really need to get some way to measure MPG (or any kind of number to ABA test ideas on). First thing up is shift points, easyish throttle (like 1/4-1/2) and shift around 2k rpm and the truck gets up to speed fairly quick, or drop the shift point to say 1700, loose a lot of boost (my big leak probably is why) and the shift starts out around 1000 rpm and takes probably 50% longer for the rev up in the given gear with even more throttle. In my mind, the slower rev up route should be bad for MPG since i theory it's dumping more fuel, but it might just be the line where the turbo is building pressure vs doing almost nothing from the leak. Would be nice to get a boost gauge too so I can see what it's actually running at. I suspect the computer is tuned to dump more fuel in the range when the boost should be good. I haven't kept a good eye on the exhaust, but a couple times I checked while taking off somewhat hard and saw no black smoke (wasted fuel), so it seems I'm getting enough air to keep things somewhat happy.
Got more parts in the mail, block heater cord is burnt in half at the engine, new one is $20 shipped. Atleast 1/2 the glow plugs are bad so bought a set of 8 (motorcraft) for $88 shipped from autozone, and since I have a 0.65v drop across the glow plug relay, I bought the upgrade relay, shipped $70.
https://www.dieselorings.com/1994-19...lug-relay.html
Check out the size difference OEM vs the monster.
Have to love vehicles that have been lacking maintenance, the good is, you know everything needs replaced, the bad is replacing everything (or upgrading when possible).
It's beyond my scope right now, but from what I read the 6 speed ZF6 is a fair bit heavier built than the ZF5 5 speed. First is lower on the 6 speed, and 6th is higher than the 5 speed's 5th so in theory could take off easier with a load, and when empty have a higher final drive ratio. I haven't done the math, but it would be interesting to look into making the axles higher geared and swap the 6 speed in so the 1-5th is roughly the same as the 6 speed and the 6th gear is like a 2nd over drive. I have to drive the truck to get a feel if any of my planned larger loads would be any issue power wise for the truck though. Lot of time and money to invest for the sake of mpg, but in theory it would make the most reliable version of the truck possible that I'm aware of. I think one of the things people have been going after is I guess the owner's manual suggests to not run in 5th gear with the ZF5 while hauling a load, but the newer manuals says it's ok to run in 6th with the ZF6. I have the 95 manual, but haven't looked for that yet.
I also noticed the dinger or whatever you'd want to call it is missing or disabled on my truck. I'm used to driving Toyota and Lexus vehicles where the headlights automatically turn off once the vehicle is turned off and the driver's door opens, caught myself leaving the lights on twice already. Need to either setup a buzzer for key off, door open, lights on, or just key off lights on would work too. Of course another route is to wire up the headlights so they turn off with the ignition switch, ideally 2 relays so if there's a failure, in theory only one would fail instead of both. Another feature I'm missing a little is the door auto unlock again on the Toyota/Lexus vehicles, unlock the driver's door 2x and it unlocks all doors, unlock the passenger side once and all doors unlock. I don't think it would be too easy to add that feature in the truck, it just makes me a little lazy vs pressing the unlock button on the door. Btw, the Lexus with these features is a 1990 lol, Toyota started with the auto headlights and such around 96ish from what I can tell. By auto lights, I do not mean a big delay after the vehicle is off. To me that's just a battery killer, if they wanted to design lights like that, just use the marker lights.
I've thought about the idea of a transmission from a buss or larger truck for my dad's truck. It sounds like they run an adapter plate factory to go from the Ford IH bolt pattern to the Allison (SAE?) bolt pattern. It would get him the trans he would like (must have over drive), but it would be quite a job getting it to fit in the truck I'd think lol. He has an old 70's manual trans from a IH buss, 4 speed, no over drive though, it had a IH gas engine, not sure if there's any difference there, same engine that was put in the IH Scouts.